1. Field of the Invention
This invention relates to an eye drop dispensing system, and, more particularly, to a portable, compact, low-cost eye drop dispensing system using a simple spring-powered pump to spray a predetermined quantity of an ophthalmic liquid into a user""s eye.
2. Description of the Prior Art
U.S. Pat. No. 5,607,410, assigned to the same assignee as the present application, shows portable eye wash systems intended for use in an emergency. These systems include a fluid reservoir having a flexible squeeze container mounted on a housing and a trough pivoted at one end to the housing. An eye piece at the other end of the trough is engaged with the user""s face adjacent his eye. For enabling the user to view his eye, a mirror is mounted on the housing. A fluid line extends from the housing along the trough to a spray outlet on the trough positioned to spray the user""s eye.
Another portable eye wash system is shown in copending Application Ser. No. 09/472,248, filed Dec. 27, 1999, which application is assigned to the same assignee as the present application. In order to facilitate single drop dosing in the system of Ser. No. 09/472,2481, two embodiments of metering spray nozzles are disclosed.
Py U.S. Pat. No. 5,163,929 shows an ocular vial for applying a 20 microliter drop of medicament into the user""s eye. A supply cavity feeds the liquid to a drop cavity which is then closed by a piston. When the piston is depressed, the drop is applied through an orifice. This device is a complex eye dropper which does not spray the liquid into the user""s eye and includes no means for positioning a spray outlet relative to the user""s eye.
Py U.S. Pat. No. 5,267,986 also shows a dispenser including a drop cavity which holds a predetermined volume of fluid to be emitted in the form of a drop. A spring causes expansion of the dispenser to emit a drop through a nozzle. A projecting finger is engaged with the user""s eyelid.
Py U.S. Pat. No. 4,946,452 also uses an eyepiece for properly positioning a medicament dispenser. An outer housing is slidably engaged over an inner housing to force the closed end of the vial towards the nozzle and displace a predetermined volume of medicament through a nozzle.
Landsberger et al U.S. Pat. No. 4,641,384 show an eyewash system including a pump operated by batteries.
Vo U.S. Pat. No. 5,171,306 provides an eye drop delivery system which ejects eye drops through nozzles mounted on the frame of a pair of glasses. A fluid reservoir and fluid driving means are located in a separate case.
Akiyama et al U.S. Pat. No. 4,215,689 show injecting apparatus held against a living body and including a reservoir in the form of a bag containing a medical liquid. A needle penetrates a thickened portion of the bag to permit flow of the liquid through a conduit. The liquid is pumped by pump means driven by movement of the living body.
Rohrbough U.S. Pat. No. 5,324,258 shows a reservoir module for a drug delivery system. A medicament vial is closed at one end by a penetrable stopper. A hollow needle pierces the stopper and provides a flow path to a peristaltic pump.
Moss et al U.S. Pat. No. 5,336,190 provide a cassette assembly for an ambulatory medical infusion pump with a reservoir bag having a tube squeezable by a pump mechanism.
Johnson U.S. Pat. No. 5,658,252 discloses a peristaltic drug pump.
As will be apparent from a review of the prior art, the pump-assisted delivery of an accurate dose of an ophthalmic rinse or medicament solution or, more generally, the pump-assisted delivery of medication to a body, have required the use of electric power or, in one case, power derived from movement of the body. It also appears from the prior act that there is a need for a cartridge enclosing a collapsible bag or container for the ophthalmic liquid which is convenient to insert and replace.
It is an object of this invention to provide an improved portable, low cost eye drop dispensing system with pump-assisted delivery of a predetermined quantity of an ophthalmic liquid as an accurate dose to an eye.
It is an additional object to provide an eye drop dispensing system with a readily replaceable cartridge enclosing a collapsible bag or chamber for the ophthalmic liquid. The cartridge comprises a cartridge housing having a spring finger formed in its top wall applying positive pressure to the collapsible chamber. The collapsible chamber has a piercable entry wall positioned to be pierced by a hollow needle extending through an opening in the cartridge housing for feeding the liquid to pump means for spraying the liquid into a user""s eye.
It is a further object to provide an eye drop dispensing system with improved pump means for delivering eye drops through a spray nozzle to a user""s eye. The pump means comprises a plunger, having a piston head movable in a cylindrical bore. The plunger is spring biased to move the piston head to a resting position in the bore, the piston head forming a wall of a dosage chamber. Actuator means is engaged by the user to engage and move the plunger in a direction expanding the dosage chamber and thereby creating negative pressure in the dosage chamber. This causes the ophthalmic liquid to flow from a liquid reservoir through a one-way valve into the dosage chamber. After the actuator means has moved the plunger a predetermined distance, an arm on the actuator means engages a sloped surface or ramp to move the actuator means out of engagement with the plunger allowing the plunger to be driven by the biasing spring to move the piston head in a direction to compress the dosage chamber and pump a predetermining dose of the ophthalmic liquid out of the dosage chamber through a second one-way valve and through a spray nozzle into the user""s eye.
The spray nozzle comprises a nozzle chamber with an end wall having a plurality of pin holes through which the liquid is sprayed. The nozzle chamber is angled to direct the liquid to the user""s eye.
The eye drop dispensing system includes a trough member with an eye piece formed on a wall at the front end of the trough member. A spray space is formed in the trough member behind the wall, and a pump housing is positioned in the trough member behind the spray space. The pump means is located within the pump housing. A cartridge receiving space is provided in the trough member between the rear end of the trough member and the pump housing. The cartridge housing is removably received in the cartridge receiving space from the rear end of the trough member. The spray nozzle is mounted at the front end of the pump housing to spray the liquid through the spray space into a user""s eye positioned above the eye piece.
Other objects, features and advantages of the invention will become apparent from the following detailed description and the drawings.